Effects of industrial tones on bowhead whale calling rates

Abstract

In summer 2012, exploratory drilling was performed by Shell at Sivulliq, a lease holding in the Beaufort Sea, located within the autumn migration corridor of bowhead whales. The drilling operation involved a number of vessels performing various activities, such as towing the drill rig, anchor handling, and drilling. We aimed to assess the effect of sounds from these activities on bowhead whale calling rates. Acoustic data were collected with six arrays of directional recorders (DASARs) deployed on the seafloor over ~7 weeks in Aug-Oct. Industrial sound was quantified with the use of indices, that measured the presence and amplitude of tones from machinery, or the presence of airgun pulses. For each 10-min period of data collected at each of the 40 recorders, the number of whale calls detected was matched with the “dose” of industrial sound received, and the relationship between calling rates and industrial sound was modeled using negative binomial regression. The analysis showed that with increasing tone ...